Creating A New Metric: Points Versus Threshold

I preface this by stating that the hard work was many years prior to penning this post by the guys at Behind The Net and Hockey Prospectus. I also directly leverage some additional work performed by Glen Miller of SNY Rangers Blog. All credit goes to them. The stat I created was simply an easier way for me to judge a player’s worth in terms of goals, points, and wins.

Since I started reading River Ave Blues many years ago, I started to “distance” myself from counting stats (goals, assists, etc) and tried to learn metrics to better quantify a player’s real worth to a team. However, as readily available as metrics were to baseball fans, it was equally unavailable to hockey fans. The guys at Behind The Net have done a great job at keeping track of a lot of advanced stats like GVT (Goals Versus Threshold), which was created by the guys at Hockey Prospectus, but it has been tough to really combine everything into one stat, like WAR in baseball, to really give you an idea about how useful a player it.

Then along comes Glen Miller of SNY Rangers Blog, who took GVT to a whole new level, and made it into a quantifiable statistic that we can use to see how many wins a player really brings to a team. First, Miller does a great job at truly defining GVT (here), and gives readers a way to really compare it to the Rangers:

…GVT…represents a player’s value above a “replacement” or “threshold” player in a term (runs for baseball or goals for hockey) fans are familiar with. A “threshold” or “replacement level” player would be defined as the top AHL/minor league player in the organization or the highest ranking free agent on the market in-season (not a prospect) and carries a GVT or RAR value of zero. Basically the guy a club would go get in the event one of their regular players went down to injury or something to that effect. For Rangers fans think Chad Kolarik, Andre Deveaux or Kris Newbury.

In essence, you really find out a player’s worth to a team when he is replaced by someone like Newbury or Kolarik (like we saw last year). Miller then takes the GVT of each Ranger from last year (courtesy of the guys at BTN), and with the assistance of Tom Awad (hockey metrics guru), created what he is calling Wins Above Threshold, or WAT.

Essentially WAT is just GVT/6, where 6 is the number of goals equivalent to a win in the standings. You can check out the full Rangers list of WAT by checking out Miller’s article, but suffice it to say, the results really shouldn’t surprise you.

Taking Miller’s work –with Awad’s help– a step (very simple step) further. Calculating wins in the standings is great, but sometimes I get the feeling that points could be better. Following up on Awad’s comment to Miller that 6 goals = 1 win, and 3 goals = 1 point, I am just going to use that information to create Points Versus Threshold, or PVT. PVT gives you the number of points in the standings that a player is worth when compared to a replacement player.

Just a note, you can also use these numbers and compare them to any other player on last year’s roster to see the difference. For example, subtracting Erik Christensen’s PVT (or WAT) from Brad Richards PVT (or WAT), and you get the difference in points or wins that the addition of Richards should bring.

I’m going to follow that up by saying this really isn’t my work, it’s combining what Miller and Awad did already into something that I personally find to be a little easier to track. Hockey is based on points, not wins (see: shootout loss), so points may be a little bit easier to judge. After the jump, you check out the calculations for this year’s Rangers roster based on last year’s GVT numbers.

The table is sorted in order, from greatest PVT to least. To use the example I used above, if you were to take Christensen’s PVT (1.80) and subtract it from Richards’ PVT (5.83), and the addition of Richards should bring about 4 extra points to the Rangers. It may not seem like much, but that’s two full spots in the playoff picture.

I want to end this post by again thanking Glen Miller, Tom Awad, and the guys at both BTN and Hockey Prospectus. This metric I made here is a product of their hard work and dedication to creating metrics for hockey.

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34 Responses to “Creating A New Metric: Points Versus Threshold”

Sadly the average fan doesn’t use metrics like this. The only stats they look at is goals assists points ppg wins losses sv% and GAA (which is a dumb stat and just tells how bad the team is or how good it is). This metric is nice but people will still Take the above mentioned stats very seriously.

I think you’d need to start by looking at these numbers by position… then, when two players are within X PAT points, you’d have to compare them observationally to determine which one brings more to the table.

But even then, Im not sure theres a reliable way to marry the two pieces together.

Tom said they are working on getting live GVT ratings posted on the Hockey Prospectus site by October. Hopefully it works out that way because I was only able to reverse-engineer it to a point. He weighted quality of ice time and I didn’t feel right about asking what factor(s) he may have used.

I believe that the point of the metrics is to put into perspective what a player is like on the ice for those who cannot watch the player. Observational analysis is very subjective, so it’s tough to really quantify that.

The best way not to twist the numbers to meet your preconceived belief is to try not to have one when analyzing the numbers. For example; I am doing a piece on Gaborik’s season and trying to find if there were other reasons his goal-scoring dropped, maybe reasons that are likely to “fix” themselves or were not necessarily his fault. One I found which suggests he is due for a bounce back is shooting percentage.